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Patagotitan
| regnum = Animalia | phylum = Chordata | clade = Titanosauria | ordo = Saurischia | subordo = Sauropodomorpha | genus = Patagotitan | species = Patagotitan mayorum }} Patagotitan is a genus of titanosaurian sauropod from the Cerro Barcino Formation in Chubut Province, Patagonia, Argentina. It contains a single species, Patagotitan mayorum, first announced in 2014 and then validly named in 2017 by José Carballido, Diego Pol and colleagues. Description Size P. mayorum has been estimated to have been 37 m long, with a weight of 69 tons}. Initial estimates placed it at 40 meters long with a weight of 77 tons. This makes it comparable to the next largest titanosaur, Puertasaurus (which has been estimated at 73-83 tons by some studies), and thus one of the largest land animals in Earth's history. Distinguishing traits The authors indicated nine distinguishing traits of Patagotitan. The first three back vertebra have a lamina prezygodiapophysealis, a ridge running between the front articular process and the side process, that is vertical because the former process is situated considerably higher than the latter process. With the first two back vertebrae, the ridge running to below from the side front of the neural spine has a bulge at the underside. Secondary articulating processes of the hyposphene-hypantrum complex type are limited to the articulation between the third and fourth back vertebra. The middle and rear back vertebrae have vertical neural spines. In the first tail vertebra, the centrum or main vertebral body has a flat articulation facet in front and a convex facet at the rear. The front tail vertebrae have neural spines of which the transverse width is four to six times larger than their length measured from the front to the rear. The front tail vertebrae have neural spines that show some bifurcation. The upper arm bone has a distinct bulge on the rear outer side. The lower thighbone has a straight edge on the outer side. Discovery Remains of Patagotitan mayorum, a part of a lower thighbone, were initially discovered in 2008 by a farm laborer, Aurelio Hernández, in the desert near La Flecha, about 160 miles west of Trelew. Excavation was done by palaeontologists from the Museum of Paleontology Egidio Feruglio. The lead scientists on the excavation were Jose Luis Carballido and Diego Pol, with partial funding from The Jurassic Foundation. At least six partial skeletons, consisting of approximately 150 bones, were uncovered, and described as in "remarkable condition". Patagotitan is one of the most complete titanosaurs currently known. The type species Patagotitan mayorum was named and described by José Luis Carballido, Diego Pol, Alejandro Otero, Ignacio Alejandro Cerda, Leonardo Salgado, Alberto Carlos Garrido, Jahandar Ramezani, Néstor Ruben Cúneo and Javier Marcelo Krause in 2017. The generic name combines a reference to Patagonia with a Greek Titan for the "strength and large size" of this titanosaur. The specific name honors the Mayo family, owners of La Flecha ranch. The holotype, MPEF-PV 3400, was found in a layer of the Cerro Barcino Formation, dating from the latest Albian. The particular stratum has an age of 101.62 plus or minus 0.18 million years ago. The holotype consists of a partial skeleton lacking the skull. It contains three neck vertebrae, six back vertebrae, six front tail vertebrae, three chevrons, ribs, both breast bones, the right scapulocoracoid of the shoulder girdle, both pubic bones and both thighbones. The skeleton was chosen to be the holotype because it was the best preserved and also the one showing the most distinguishing traits. Other specimens were designated as the paratypes. Specimen MPEF-PV 3399 is a second skeleton including six neck vertebrae, four back vertebrae, one front tail vertebra, sixteen rear tail vertebrae, ribs, chevrons, the left lower arm, both ischia, the left pubic bone and the left thighbone. Specimen MPEF-PV 3372 is a tooth. Specimen MPEF-PV 3393 is a rear tail vertebra. Specimen MPEF-PV 3395 is a left humerus as is specimen MPEF-PV 3396, while specimen MPEF-PV 3397 is a right humerus. Specimen MPEF-PV 3375 is a left thighbone while MPEF-PV 3394 is a right one. Specimens MPEF-PV 3391 and MPEF-PV3392 represent two calfbones. The animals found, though excavated in a single quarry, did not all die at the same time. Within the 343 centimeter thick sediment containing the fossils, three "horizons" are present of events in which young adult individuals perished during floods. The water did not transport the carcasses any further but covered them with sandstone and mudstone. The animals were about the same size, differing no more than 5% in length. As far as can be ascertained, all bones discovered belong to the same species and are thus part of a monospecific assemblage. References Category:Dinosaurs Category:Cretaceous dinosaurs Category:Herbivores Category:Sauropods Category:Dinosaurs of South America Category:Argentina Dinosaurs Category:Pages in need of sourcing Category:Fossil taxa described in 2017 Category:Titanosaurs